Innovative deep-sea analysis protects the environment: double-pulse LIBS technology

Hinweis zur Verwendung von Bildmaterial: Die Verwendung des Bildmaterials zur Pressemitteilung ist bei Nennung der Quelle vergütungsfrei gestattet. Das Bildmaterial darf nur in Zusammenhang mit dem Inhalt dieser Pressemitteilung verwendet werden. Falls Sie das Bild in höherer Auflösung benötigen oder Rückfragen zur Weiterverwendung haben, wenden Sie sich bitte direkt an die Pressestelle, die es veröffentlicht hat.

Illustration of a diving robot that uses laser-induced plasma spectroscopy (LIBS) to analyse materials in the deep sea in an environmentally friendly way. | Copyright: INP | Download

With laser-induced plasma spectroscopy (LIBS) using double-pulse lasers, the Laser Zentrum Hannover e.V. (LZH) has developed a method for the environmentally friendly analysis of materials at a depth of 6,000 metres below sea level. Together with the Leibniz Institute for Plasma Science and Technology (INP) in Greifswald, the fundamental process behaviour was investigated as part of a DFG project. The method provides precise elemental analysis in real time and replaces time-consuming sampling of the seafloor.

The double-pulse technique uses two laser pulses: the first pulse creates a cavity in the water at the surface of the material, while the second pulse evaporates material from the surface and creates a plasma containing the elements for spectroscopic analysis. The problem is the high pressure underwater, which makes it difficult to generate meaningful spectra for accurate analysis.

Optimised for deep sea use

The current research focuses on analysing materials at pressures of up to 600 bar, such as those found 6,000 metres below the surface, and using laser pulses with energies of up to 150 millijoules. By adjusting the laser parameters, the team was able to optimise the measurements for the high pressure of the deep sea. The short delays of 0.5 microseconds between the laser pulses and the precise adjustment of the start times of the spectrometer measurements are crucial for the quality of the data obtained.

The research has been published in the journal Spectrochimica Acta Part B: Atomic Spectroscopy (DOI:10.1016/j.sab.2024.106877). The project was funded by the German Research Foundation (DFG) under the project number 454848899.

Originalpublikation:
https://doi.org/10.1016/j.sab.2024.106877